In the field of agriculture, crop and plant protection as well fertilisation are some times necessary to provide for a lucrative harvest. Crop protectants and fertilizers need to be deployed with high efficiency in order to be cost-effective. This can be achieved by the present invention, because the atomizing device provides for a highly efficient dispersion or atomization of the fluid. Within the context of the present invention, fluid encompasses any liquid material, dispersions, suspensions and emulsions.
In the field of fire-fighting, one method to extinguish a fire is to use water. The first way water extinguishes a fire is by cooling, which removes heat from the fire. This is possible through the water's ability to absorb massive amounts of heat by converting water to water vapor. The second way water extinguishes a fire is by smothering the fire. When water is heated to its boiling point, it converts to water vapor. When this conversion takes place, it dilutes the oxygen in the air with water vapor, thus removing one of the elements that a fire requires to burn. This can also be achieved with foam. It is therefore of paramount importance to have the fire extinguishing media being dispersed in as small as possible droplets to provide a high surface area for the cooling and smothering effect.
In the field of combustion processes, known from e.g. coal-fired power plants, which use power boilers for producing electricity world wide; coal, previously referred to as pitcoal or seacoal, a fossil fuel extracted from the ground by underground or surface mining is burnt in particular furnaces. Depending on the type of coal (anthracite, bituminous, subbituminous or lignite) and whose abundance varies within geographical regions, the sulphur content in such coals varies significantly and increasingly in the order mentioned before. Thus lignite is a type of coal with sulphur content up to 10% by weight of the coal and sometimes even more. The problematic of the sulphur content becomes evident, as during the combustion process of coal, besides the formation of carbon dioxide (CO2), the sulphur is transformed into sulphur dioxide (SO2), which accounts for the largest human-caused source of SO2, a pollutant gas that contributes to the production of acid rain and causes significant health problems. Other contaminants, such as nitrogen oxides (NOx), hydrochloric acid and heavy metals such as mercury, arsenic, lead, selenium and cadmium are hazardous compounds which are further produced and/or accumulated during such combustion processes.
The combustion processes are, however, not restricted to power plants only. There exist other technologies which use high temperature processes in boilers, such as the paper industry, the steel industry, the waste incineration industry, or mineral material producers, just to mention some.
For many decades environmental concerns and thus the evolving environmental regulations have led to steady improvements in these high temperature process technologies. Particularly, the pollutants, toxic wastes, and fine particles have been targeted to be captured and thus eliminated from the exhausts of the combustion and/or heat processes to reduce their release into the atmosphere and to reduce corrosion within such systems. One way of reducing carbon dioxide to be released into the atmosphere was to increase the efficiency of coal burning or improved reaction processes. However, it is not possible to avoid the formation of such pollutants and therefore there is still a high demand in processes which allow the capture of such pollutants and to remove them from the exhausts to provide exhausts which are almost free of such contaminants. Such processes are known to the skilled person.
In order to comply with the environmental regulations and to meet the limitations affecting the release of pollutants into the atmosphere, the combustion products formed in the industrial combustion processes are passed through flue gas desulfurization (FGD) systems. The treatment of flue gas to capture SO2 is often carried out in lime- or limestone-based wet scrubbers, in which the lime or lime-stone slurries are contacted with the flue gas before the flue gas is discharged into the atmosphere. The effectiveness of such scrubbers are quite satisfying in capturing the 1%-2% of the sulphur present in the fuel, however, they require important investments.
A different method uses the injection of a lime- or limestone slurry into the high temperature region of the boiler, a technology known as LIMB (Limestone Injection Multistage Burner). This technology however is not able to capture more than 60% to 65% of the formed SO2.
A further method is the Furnace Sorbent Injection method (FSI) wherein lime and limestone are injected in the form of a slurry into the furnace with an effectiveness of sulphur capture of 10% to 60%. Another suitable sorbent is dolomite, which however does not exceed the effectiveness mentioned before.
In order to finely spray liquids or solid particles containing slurries or dispersions in the form of fine droplets, the application US 2010/0163647 which refers to a two-fluid nozzle allows to obtain a large spray jet opening angle with fine droplet atomization. Formation of large droplets at the edge of the nozzle is prevented by an annular clearance atomization at the edge of the nozzle by secondary air branched off directly from the annular chamber surrounding the mixing chamber. Pressure gas leaving the annular clearance with high velocity ensures that a liquid film on the wall of the nozzle orifice of the divergent section is drawn out to a very thin lamella, which then is broken down into small droplets. Part of the pressure gas is thus diverted into the mixing chamber and part of it to the edge of the nozzle orifice.
US 2007/0194146 provides for a nozzle capable of multiple atomizing steps of a liquid, wherein the liquid is atomized in a first direction and subsequent post atomization of the same liquid in a second direction is made to form a counter flow nozzle. Accordingly, the liquid to be dispensed is atomized in at least two separate stages.
U.S. Pat. No. 5,004,504 refers to the preparation of red transparent iron oxide by spray drying. A filter cake is disbursed in the form of small droplets by a two fluid nozzle, said nozzle comprising a cylindrical central conduit and an annular conduit surrounding the cylindrical conduit. The process fluid, which as an aqueous mass of yellow transparent iron oxide, is passed through the central conduit while an atomizing fluid supplied through the surrounding annular conduit is forced under pressure through the annular conduit. No or little pressure is needed to transport the aqueous mass of yellow transparent iron oxide through the central conduit. Atomizing of the obviously thick aqueous mass of transparent yellow iron oxide is achieved as a result of using a high pressure atomizing fluid such as compressed air or super heated steam at pressures of from about 5.5 bar to about 6.8 bar or even higher.
Thus the prior art related to an atomization process provides for different tailor made nozzle geometries to be used in different applications each seeking to have the best efficiency.